Recent research has shown that investors' emotional behaviors play an important role in determining prices and explaining returns, especially for stocks that have higher subjective valuations and greater limitations in arbitrage. The purpose of this research is to investigate the relationship and degree of effectiveness of oil price changes and investors' emotional behaviors with stock returns in petrochemical and refining companies. To achieve the research objective and to statistically analyze the data, the autoregressive distribution lag (ARDL) model was used. The statistical population of the research includes petrochemical and refining companies listed on the Tehran Stock Exchange. The selected sample in the period 2011-2024, considering the specified filters, is fifteen companies from the mentioned statistical population. The results of this study show that oil price changes and investors' emotional behaviors have a significant relationship with stock returns in petrochemical and refining companies listed on the Tehran Stock Exchange. The innovation of the research is in simultaneously examining the effects of three new variables in Iran's petrochemical and refining industry.